One summer evening, my dog and I were walking on a trail through the woods when I noticed her racing around the corner ahead, her nose held high in the air like a cartoon dog following a cartoon scent. As I hurried after her, I began to smell a truly foul odor. Was there any chance that she hadn’t rolled in whatever that was? I rounded the corner and came upon her standing in the middle of the trail, craning her neck toward the top of a group of evergreens and twitching her nose eagerly like a rabbit. I followed her gaze to a pair of Turkey Vultures perched 15 feet above us. They simply reeked of whatever had been the day’s fare and neither one seemed to notice nor care. As the pair took off a minute or so later—and REALLY stirred up the stench—I felt an appreciation of these ecologically critical, yet incredibly smelly, garbage processors of Nature. As my dog and I ambled on, I found myself thinking, “Well, as long as you and your date both order the onions and garlic, neither one is offended.”
Colorado’s scavenger in the skies, the Turkey Vulture is a large, dark bird with a seemingly shrunken, featherless red head. (Males and females look pretty much the same, unless you’re a Turkey Vulture.) When perched, it appears rather humpbacked, giving the bird a brooding look—think of Snoopy, keeping a scowling lookout on the roof of his dog house. You can sometimes spot a group of them standing along roadsides or in pastures or, the most common view for me, soaring overhead. On the ground, Turkey Vultures may be mistaken for their namesakes, Wild Turkeys. But if you see a flock of large birds walking and foraging—not in a huddle—they aren’t vultures. Vultures basically just stand around a dead animal and pull off pieces of meat. A consummate soaring bird, a Turkey Vulture rarely flaps once aloft; when it does, its wingbeats are slow and deep. When seen gliding overhead, its wings show a distinctive, thin, dark leading edge (the edge of wing toward the front of the bird) followed by a broad silvery band outlining the remainder of the wings. The bird holds its wings in a deep V (called a “dihedral”) and soars in an often wildly teetering manner, to maximize its ability to soar at lower altitudes, where it hunts for food.
Vultures find most of Colorado suitable for summer living, although the plains north of the Arkansas River Valley rarely host Turkey Vultures, as is true for the high mountain valleys and the high peaks surrounding them as well. These areas just don’t have enough solar heating and exposure to westerly winds to create the abundant thermal upwellings that Turkey Vultures rely on for their flapless soaring. While vultures in the southern U.S. remain year-round, those in our area migrate. Spring migration peaks in April; fall migration, in late September to November.
A vulture’s menu features primarily one entrée—carrion. Road kill, livestock dead in a field, dead fish washed up on a lake shore all can attract a group of vultures. But not just any old carrion. They appear to prefer fresher carrion to seriously putrid carrion. (Who knew they were so fussy?) Unusual among birds, Turkey Vultures actually have extremely good senses of smell and can locate meals by scent even when soaring. In fact, their rather unattractive featherless heads provide a real bonus for birds that spend much of their dining experiences with their heads stuck inside rotting carcasses.
Turkey Vultures do not reach sexual maturity until 5 years of age and may not breed every year even then. They form long-term monogamous pair bonds but may pair again if a mate dies. Solitary nesters, they primarily require a nest site isolated from humans and their many disturbances. In Colorado, caves and deep crevices in cliffs are the preferred nest sites, although nests have been found on rocky outcroppings and even on Anasazi ruins in Mesa Verde National Park. Vultures lay eggs—usually 2 in a clutch—from April to June; the eggs hatch in 38 – 41 days. Unlike many other species, both parents incubate the clutch about equally. Turkey Vultures have weak feet, so they can’t carry prey to their nest sites. However, they compensate by regurgitating food for the nestlings; a nestling thrusts its bill into the adult’s to receive the partially digested slurry. The young make their first forays out of the nest 70 – 80 days after hatching. Fledging is a protracted process, and the youngsters spend an addition 1 – 3 weeks after their first ventures out of the nest, hanging out at nest site, being fed by parents, and gradually flying around the area to explore and practice their soaring skills. They typically leave the nest area by 12 weeks of age, often joining a communal roost if one is nearby.
The Turkey Vulture’s scientific name—Cathartes aura—reflects its importance to the environment as a heavy-duty scavenger. The genus name comes from kathartes (Greek), meaning “a cleanser or purifier”—an ironically honorable name for an often stinky bird, I’d say. The species name derives from auroura, an indigenous Mexican tribe’s word for this bird. Its common name refers to its resemblance to a turkey because of its bare red head and dark feathers. And vulture, from the Latin vulturus, means “one who tears”—referring to its feeding habits of ripping off hunks of carrion.
The American Ornithologists Union (AOU), the determiner of all things about avian taxonomy in the Americas, had traditionally placed vultures in the same family as raptors such as hawks and eagles. In a surprising move in 1998, based on DNA analyses, the AOU moved vultures to the stork family, bringing together the birds most associated with the “bookends” of the life cycle. (Okay, show your age here. Who remembers the 1960s television show, Ben Casey? Man, woman, birth, death, infinity…) Unfortunately, this lovely pairing didn’t last. In 2007, based on even more sophisticated DNA analyses, the AOU moved vultures back to the hawk and eagle family. Science wins out over delicious, symbolic symmetry.
You can learn more about vultures here.